#include <iostream> #include <cstring> using namespace std; #define MAX_LENGTH 100 char jia(charx,chary); char jian(charx,chary); void duiqi(charx,chary); char jiaqian(char m,charx); int main() { char x[100],c[2],y[100]; cin>>x>>c>>y; duiqi(x,y); if(c[0]=='+') cout<<jia(x,y); if(c[0]=='-') cout<<jian(x,y); return 0; } char jiaqian(char m,charx){ int k=strlen(x); char *p=x; char tmp=m; for(int i=0;i<=k;i++){ *(p+1)=p; p++; } x[0]=tmp; return x; } void duiqi(charx,chary){ int a=strlen(x); int b=strlen(y); if(a>b){ charp=y; for(int i=0;i<b;i++){ *(p+a-b)=*p; p++;} p=y; for(int i=0;i<a-b;i++){ p=0; } } if(a<b){ chap=x; for(int i=0;i<a;i++){ (p-a+b)=p; p++;} p=x; for(int i=0;i<b-a;i++){ p=0; } } } char jia(charx,chary){ int m=atrlen(x); int k=0; charp=x+m; charq=y+m; for(int i=0;i<m;i++){ p=p+q+k; if(p>=10){ p=p-10; k=1; } else{ k=0; } p--; } if(k==1) x=jiaqian('1',charx); return x; } char jian(charx,chary){ int m=atrlen(x); int k=0; if(y[0]=='0'){ charp=x+m; charq=y+m; int o=1;} else{ charp=y+m; charq=x+m; int o=0; } for(int i=0;i<m;i++){ *p=*p-*q+k; if(*p<0){ *p=p+10; k=-1; } else{ k=0; } p--; } if(o==0) x=jiaqian('-',charx); return x; }

这段代码有许多问题，例如函数的参数没有定义类型，函数内部使用的变量没有定义，变量名和函数名重复等等。此外，函数的返回值也没有定义类型。以下是修正后的代码：

#include <iostream>
#include <cstring>
using namespace std;

#define MAX_LENGTH 100 

char* jia(char* x, char* y);
char* jian(char* x, char* y);
void duiqi(char* x, char* y);
char* jiaqian(char m, char* x);

int main() {
    char x[MAX_LENGTH], c[2], y[MAX_LENGTH];
    cin >> x >> c >> y;
    duiqi(x, y);
    if (c[0] == '+')
        cout << jia(x, y);
    if (c[0] == '-')
        cout << jian(x, y);
    return 0;
}

char* jiaqian(char m, char* x) {
    int k = strlen(x);
    char* p = x;
    char tmp = m;
    for (int i = 0; i <= k; i++) {
        *(p + 1) = p;
        p++;
    }
    x[0] = tmp;
    return x;
}

void duiqi(char* x, char* y) {
    int a = strlen(x);
    int b = strlen(y);
    if (a > b) {
        char* p = y;
        for (int i = 0; i < b; i++) {
            *(p + a - b) = *p;
            p++;
        }
        p = y;
        for (int i = 0; i < a - b; i++) {
            *p = '0';
            p++;
        }
    }
    if (a < b) {
        char* p = x;
        for (int i = 0; i < a; i++) {
            *(p + b - a) = *p;
            p++;
        }
        p = x;
        for (int i = 0; i < b - a; i++) {
            *p = '0';
            p++;
        }
    }
}

char* jia(char* x, char* y) {
    int m = strlen(x);
    int k = 0;
    char* p = x + m - 1;
    char* q = y + m - 1;
    for (int i = 0; i < m; i++) {
        *p = *p + *q + k - '0';
        if (*p > '9') {
            *p = *p - 10;
            k = 1;
        }
        else {
            k = 0;
        }
        p--;
        q--;
    }
    if (k == 1)
        x = jiaqian('1', x);
    return x;
}

char* jian(char* x, char* y) {
    int m = strlen(x);
    int k = 0;
    int o = 0;
    if (y[0] == '0') {
        char* p = x + m - 1;
        char* q = y + m - 1;
        o = 1;
    }
    else {
        char* p = y + m - 1;
        char* q = x + m - 1;
    }
    for (int i = 0; i < m; i++) {
        *p = *p - *q - k;
        if (*p < '0') {
            *p = *p + 10;
            k = 1;
        }
        else {
            k = 0;
        }
        p--;
        q--;
    }
    if (o == 0)
        x = jiaqian('-', x);
    return x;
}

这个程序实现了两个大整数的加法和减法，并且能够对输入的两个数进行长度对齐。但是仍然存在一些问题，例如在进行减法时，没有考虑到被减数小于减数的情况，还有就是对于输入的数字长度没有进行判断，如果输入的数字过长，会导致程序崩溃。因此，还需要进一步完善。